The previous approach of `paths-ignore` was flawed because currently
it doesn't interact well with GitHub's "Require status checks to pass
before merging" setting. As a result, PRs that didn't trigger all
workflows couldn't be merged, because GitHub waited for the skipped
workflows to finish.
`dorny/paths-filter` is a somewhat elegant workaround proposed in
https://stackoverflow.com/questions/66751567.
* dev: run workflows only if certain file paths change
* fix: looks like you can't ? a /
* feat: simpler approach
Don't run Rust if only package.json, package-lock.json or anything under
web/packages has changed.
Don't run either if they only have docs changes.
relrelb